Alcohol Use During Smoking Cessation Predicted Failure, but Marijuana Use Did Not | Research

The takeaway

Among 199 smokers in a cessation program, even low-to-moderate alcohol use during treatment predicted relapse at all follow-up points, while marijuana use neither at baseline nor during treatment predicted smoking outcomes.

Read this if you use marijuana and are trying to quit tobacco, and want to know if cannabis use affects your chances.

Marijuana use did not predict smoking cessation failure, but alcohol use did

What the researchers found

Researchers examined how alcohol and drug histories affected smoking cessation in 199 clinic patients. Nearly a quarter (23%) had a history of alcohol or drug problems, 79% used alcohol, and 21% used marijuana during treatment.

History of substance abuse did not predict cessation outcomes. But current substance use patterns diverged sharply. Alcohol use, even at low-to-moderate levels, predicted smoking at every follow-up assessment. Participants who used any alcohol during treatment had significantly lower quit rates.

Marijuana use told a different story. Neither baseline marijuana use nor marijuana use during treatment predicted smoking outcomes. Marijuana users quit smoking at the same rates as non-marijuana-users.

This finding was surprising given previous research linking marijuana to smoking cessation failure, suggesting the relationship may be more nuanced than earlier studies indicated.

Why it matters

This study challenged the assumption that marijuana use necessarily undermines tobacco cessation. By separating alcohol and marijuana effects, it showed that alcohol was the primary substance-use barrier to quitting smoking, while marijuana was neutral.

The numbers in context

199 participants. 23% had alcohol/drug problem history. 79% used alcohol. 21% used marijuana during treatment. Alcohol predicted smoking at all follow-up points. Marijuana predicted nothing.

How the study worked

Prospective study of 199 smokers in a cessation clinic. History of alcohol/drug problems, current alcohol use, and current marijuana use were assessed. Abstinence was measured at multiple follow-up points.

What this study cannot tell us

Relatively small sample (199). Marijuana use was self-reported and the 21% rate may reflect varying use levels. The study may not have been powered to detect smaller marijuana effects. The clinic population may not represent all smokers.

How to read the evidence

A prospective clinic study with multiple follow-up assessments. Good design but modest sample size and potential for unmeasured confounders.

When this study was published

Published in 1999. Research on cannabis-tobacco interactions continues with mixed findings across different populations.

The bigger picture

This finding contrasted with a 1994 study showing marijuana use halved tobacco cessation success. The discrepancy likely reflects different populations, settings, and levels of marijuana use, illustrating how context matters when studying substance interactions.

Questions still open

Why did this study find no marijuana effect while an earlier study found a strong one? Does the level of marijuana use matter (occasional versus daily)? Could marijuana be used as a substitute to reduce cigarette cravings?

Common questions

Does marijuana use make it harder to quit smoking?

In this study, no. Marijuana use at baseline and during treatment did not predict smoking cessation outcomes. Alcohol use, by contrast, predicted failure at every follow-up point.

Does having a drug history matter?

No. A history of alcohol or drug problems did not predict cessation outcomes. What mattered was current substance use during the quit attempt.

Read the original research

History of alcohol or drug problems, current use of alcohol or marijuana, and success in quitting smoking.

Addictive behaviors, 24(1), 149-54

View on PubMed ↗

Citation

Humfleet, G; Muñoz, R; Sees, K; Reus, V; Hall, S. (1999). History of alcohol or drug problems, current use of alcohol or marijuana, and success in quitting smoking.. Addictive behaviors, 24(1), 149-54.